code: def testUnknownShape(self):
      def create_placeholder(shape, dtype):
          with ops.Graph().as_default():
              return array_ops.placeholder(dtype=dtype, shape=shape)
  
      values = [
          array_ops.ones([10, 10], dtype=dtypes.float32),
          create_placeholder([None, 10], dtype=dtypes.float32),
      ]
      packs = cross_device_utils.group_by_size(values, bytes_per_pack=1)
      self.assertLen(packs, 1)
      self.assertEqual(packs[0], values)
  
imports: from absl.testing import parameterized
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import cross_device_utils
  from tensorflow.python.distribute import device_util
  from tensorflow.python.eager import test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import indexed_slices
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
label_desc: Use image node_id 3 for calling the GroupBySizeTest obj's underlying member method code with example usage: obj.testUnknownShape() and returns: array_ops